Assign a relationship after loop in php - php

Question

I want to loop over a collection of items and attach a relationship based on if a particular condition is satisfied. Here is my code
public function bulkAssign()
{
$trainers = MasterTrainer::all();
for ($i=0; $i < count($trainers); $i++) {
$this->assignToManager($trainers[$i]);
}
// return redirect()->back()->with('success', 'Project Managers Assigned Successfully');
}
private function assignToManager($trainer)
{
$manager = ProjectManager::where('state', $trainer->state)->first();
return $trainer->update([
'project_manager_id' => $manager->id
]);
}
What I get is it attaches only the first manager to all the elements in the collection. What am i doing wrong?

Answer 1

can you inline the func for now? do some sort of echo/debugging?
but also I see several issues:
yes do use foreach because that is a bit better and you avoid having to use $i (making code a little more easy to read)
you are not attaching a relationship, you are setting a project_manager_id (i say this because initially i automatically thought you were going to dynamically add a relationship to model)
without knowing your db schema.. could you not do some sort of trick to avoid having to do this nth times?
$manager = ProjectManager::where('state', $trainer->state)->first();
you could either do:
$states = $trainers->pluck('states');
$managers = // do a query to get one trainer per state using group by
foreach ($trainers... ) {
$manager = $managers->where('state', $trainers->state)->first() // this is collection not eloquent
$trainer->update([
'project_manager_id' => $manager->id
]);
other would be to create a scope where you do a sub query to get manager id when u query for trainers